Method and apparatus for palletizing elongated bags of container ends

ABSTRACT

A palletizing mechanism (PP, WB, HB 1 - 1 , HB- 2 ) supplies a pallet and a length of wrapping paper for receiving successive rows of bags until a full pallet load is prepared. The palletizing apparatus can be mated to the bagger apparatus, and operated synchronously therewith under the management of a common programmable controller. The palletizer apparatus receives each stick of can ends in a predetermined orientation, and maintains the orientation vis-a-vis all sticks in a pallet load. The sticks are placed sequentially into a row of predetermined number of sticks, then that row is loaded onto the top of a layer of wrapping, the first row being supported on a suitable empty pallet, then the wrap is passed over the last placed row. This operation proceeds with the wrap supply following a to-and-fromotion until the desired number of rows is automatically built up on a pallet.

RELATED APPLICATIONS

This application is related to U.S. Provisional Patent Application Ser.No. 60/060,518 filed 30 Sep. 1997 entitled Bagger & Palletizer for CanEnds, and to copending International Patent Application No.PCT/US98/20395 entitled Bagger filed on the same date as thisapplication.

TECHNICAL FIELD

This invention relates to methods and apparatus for packaging can ends,e.g. disc-like end units which have a preparatory curl on their edge andwhich may also have attached easy-open tabs. In practice such apparatusis often called a bagger, since the preferred manner of packaging theends places a stack (usually called a “stick”) of the ends in a tubularbag which is then folded closed at its initially open end. The inventiondisclosed relates to methods and apparatus for assembling and placingthe sticks on pallets.

BACKGROUND ART

In the early 1970s can ends were placed manually into bags, and the bagswere loaded manually into pallet for use at filing/closing machinery. Inthe mid-1970s semi-automatic bagging equipment was introduced in aneffort to keep up with the increased output of newer conversion presses,and that development led to automatic bagging machines, which were firstintroduced in the mid-1980s. Some of the impetus for this developmentwas the monotony of repeated manual operations, which also appeared tobe the cause of repeated strain to the hands of those doing the bagging.

Those automatic machines formed a “stick” of ends and then packagedthem 1) by wrapping them from a coil or reel of paper or plastic, or 2)placing the sticks into preformed bags. It was found that kraft paperwas the preferred wrapping material since it can be recycled, and sinceit will “breathe” to void fumes which may linger with the stick of endsfrom synthetic sealing compounds applied to the ends in an earlieroperation, or to void moisture which may linger from water basedcompounds.

In the early patent prior art, the disclosures in U.S. Pat. Nos.3,337,064, 3,417,853, 3,545,631 and 3,618,530 are representative ofsystems which use a pneumatic or similar input conveying system for theindividual can ends, and troughs or the like for gathering the ends in aface to face on-edge stack. Mechanical feeding mechanisms engage thecurl edges of the generally vertically positioned ends and move theminto the input or receiving end of a stack forming in a trough, then theends are supplied to a filling and closing (end curling) machine.Wrapping a stack is not disclosed, and the filled trough is intended tofunction as a reservoir for smooth steady supply of ends to the closingmachine.

In U.S. Pat. Nos. 3,722,741, 4,000,709, 4,537,550, 4,676,708 and5,335,810 more sophisticated buffer systems for stacks of ends aredisclosed, wherein the stacks are separated according to a count ofstacked ends, and those stacks are loaded into successive verticallyarranged carriers on an endless, carrousel-type conveyor which suppliesthe stacks to a closing machine.

U.S. Pat. No. 3,878,945, and its various divisions U.S. Pat. Nos.3,962,845, 3,971,189, 4,051,965, and 5,119,617, all disclose features ofan automatic bagging system in which ends are supplied to a gatheringand counting deice which separates ends into stacks (or “sticks”),wrapping devices for loading the stacks into individual bags, andmechanism for loading the wrapped stacks onto pallets.

U.S. Pat. No. 4,364 relates to a conveying improvement for gatheringends, providing temporary spacing thereof to facilitate curing ofpreviously applied end seam compound. U.S. Pat. No. 4,655,350 disclosesan improvement for detecting and removing ends which have been reversedface-to-back (e.g. public to product sides) in the formation of a stack.U.S. Pat. No. 4,742,669 discloses and improved end counting device inthe end counting and stack forming systems. U.S. Pat. No. 5,005,340discloses a system for inspecting an assembled stack of ends. U.S. Pat.No. 5,372,245 discloses an improved drive for an in-feeding array ofassembled ends. U.S. Pat. No. 5,524,947 discloses an improved mechanismfor picking and placing stacks (also called “sticks”) of ends in thebagging and palletizing process.

U.S. Pat. Nos. 4,537,010 and 5,372,473 disclose more advanced devicesfor handling bagged stacks of ends and placing them into pallets.

Thus, prior art automatic bagging machines allow lanes of ends from theoutput of a conversion press to be counted, separated in stacks orsticks, the stacks placed into individual bags, and the bagged stacksare then loaded into a common palletizer, from which a supply isprovided to one or more filling and closing devices.

DISCLOSURE OF THE INVENTION

A palletizing mechanism supplies a pallet (support) and a length ofwrapping paper (usually Kraft paper or the like) for receivingsuccessive rows of bags until a full pallet load is prepared. Thepalletizing apparatus can be mated to the aforementioned BaggerApparatus, and operated synchronously therewith under the management ofa common programmable controller; an Allen-Bradley Model No. H-4030 isemployed in an actual embodiment. The palletizer apparatus receives eachstick (closed bag of can ends of predetermined count) in a predeterminedorientation, and maintains the orientation vis-a-vis all sticks in apallet load. The sticks are placed sequentially into a row ofpredetermined number of sticks, then that row is loaded onto the top ofa layer of wrapping, the first row being supported on a suitable emptypallet, then the wrap is passed over the last placed row. This operationproceeds with the wrap supply following a to-and-fro motion until thedesired number of rows is automatically built up on a pallet.

Other objects and advantages of the invention will be apparent from thefollowing description, the accompanying drawings and the appendedclaims.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a schematic plan view of the major components of the system;

FIG. 2 is an enlarged schematic plan view of the palletizer and itscomponents;

FIG. 3 is a perspective view of the Pick and Place mechanism in thepalletizer;

FIG. 4 is a perspective view of the walking beam mechanism;

FIG. 5 is a perspective view of the first palletizer hold back device;

FIG. 6 is a pictorial view of the stick crowder device;

FIG. 7 is a pictorial view of the second palletizer hold back and rowtransport mechanism;

FIG. 8 is a perspective view of the row offset control cylinder;

FIG. 9 is a perspective view of the main table in the palletizer;

FIG. 10 is a perspective view of the empty pallet storage lift;

FIG. 11 a perspective view of the empty pallet shuttle;

FIG. 12 is a pictorial view of the full pallet lift;

FIG. 13 is a perspective view of the row cutoff and row tamp devices;

FIG. 14 is a perspective view of the row supports;

FIG. 15 is a perspective view of the snake wrap carriage, including thepaper stuffer and cardboard lift vacuum cup;

FIG. 16 is a perspective view showing the snake wrap paper cutter;

FIG. 17 is a pictorial view of the full pallet lift and pallet dischargeroller table;

FIG. 18 is a pictorial view of the partial pallet restart alignment arm;

FIG. 19 is a side view of the thread up schematic for the snake wrap;

FIG. 20 is a perspective view of the snake wrap carriage, viewed fromground level; and

FIGS. 21A-1, 21A-3, 21B-1, and 21-B-3 are together the Process FlowChart for the palletizer operation.

DESCRIPTION OF THE PREFERRED EMBODIMENT BEST MODE FOR CARRYING OUT THEINVENTION

The present invention is directed to an improved palletizer apparatuswhich is part of a bagger/palletizer system.

To understand the following description, it is desirable to includefirst definitions of certain terms, as follows:

-   -   A “Stick” is a bag filled with a predetermined number of can        ends or lids;    -   A “Skid” refers to the wooden structure on which a pallet of        sticks is built; Filled pallets are formed in the palletizer        apparatus;    -   “Bagger” refers to the portion of the system that forms the        sticks by counting ends from the lead (foremost) end in a stream        of can ends which are supplied to the bagger apparatus along        in-feed rails, the ends being placed on edge and moving        face-to-face along such rails; The bagger counts a predetermined        number of ends, separates them from the following stream, and        places them into a bag, then folds and seals the bag; Sticks are        formed in the bagger apparatus, as disclosed in the related        International Application PCT/US98/20395.

“Palletizer” refers to the portion of the system that builds layers offilled, sealed bags and places them onto a skid.

The Palletizer

The Pick and Place, seen in FIG. 3, removes the filled, sealed bags,from the stick discharge grippers of the bagger folding mechanism, andplaces them on the walking beam mechanism WB (FIG. 4). The walking beammechanism in turn places each of the sticks in the appropriate positionin the staging area. The first (or temporary) hold back device PH-1(FIG. 5), is comprised of three fingers PH-11 which can inhibit thefirst stick from rolling, and retain the row until the Primary Hold backis reached.

As each stick is placed, the Stick Crowder, also seen in FIG. 6, forcesthe factory sealed or closed end (against which the ends are pushed inthe stick formation) of the bag against a stainless steel place toensure that each row of the pallet is properly packed.

The Primary Hold back retains the row during building while sticks 8-16are placed. In conjunction with the Pull Off, the Primary Hold backtransfers the completed layer to the Main Table.

FIG. shows the Pull Off, which clamps the row against the Primary Holdback, and transfers the completed layer of the pallet from the stagingarea to the Main Table.

The Main Table is a movable platform that extends over the pallet andplaces a completed layer of sticks.

The Skid Storage Lift is the loading point for the empty skids. The Xand Y Skid Positioners locate the top skid against the Skid Back Stop.

FIG. 11 shows the Skid Shuttle, which contains the Skid Grippers thatclamp and align the top skid and transport it to the Pallet Lift area.

The Pallet Lift is the hydraulic lift on which the skid is filled withcompleted layers. The Pallet Lift has a motorized roller table totransport the finished pallet to the Pallet Discharge Roller Table forremoval by the operator.

The Row Cut Off, shown in FIG. 13, inhibits the row of sticks fromretracting with the Main Table.

The Front and Rear Vertical Tampers, also shown in FIG. 2.22, compactthe pallet as each new layer is placed.

The Upper Side Guides impose the row offset and retain the layer ofsticks as it is placed on the pallet. The Lower Side Guides restrain thepalliated layer, and support and compact the new layer being placed.

-   -   1. The Snake Wrap Carriage, seen in FIG. 20, covers each        completed layer with paper after the layer is transferred to the        Pallet Lift.    -   2. The Paper Stuffer (Area 6, FIG. 2) tucks the first layer of        paper underneath the cardboard on the skid.    -   3. The Snake Wrap Paper Cutter cuts the wrap at the completion        of the pallet.

The Pallet Discharge Roller Table, shown in FIG. 17 is a motorizedroller table that moves the completed pallet away from the palletbuilding area for removal by the operator. This section describes theprocedures required to prepare the system for operation. It is dividedinto two sections; Palletizer and Bagger.

FIG. 19 is a schematic of the Snake Wrap Carriage that shows the properthread up of the Snake Wrap Roll from the Snake Wrap Catwalk vantagepoint. FIG. 20 is a pictorial view from the same vantage point.

To load the Snake Wrap roll from the catwalk during system set-up,referring to FIGS. 19 and 20:

-   -   1. Open the Snake Wrap Catwalk door guard.    -   2. Remove the Split Collar from the Paper Roll Cylinder.    -   3. Align the Paper Roll such that the paper feeds        counterclockwise from the top of the roll.    -   4. Slide the properly aligned Paper Roll onto the Paper Roll        Cylinder.    -   5. Replace the Collar.    -   6. Thread the paper into the pinch rolls ensuring that the paper        feeds underneath the tensioning rod prior to the pinch rolls.

7. Feed the paper between the stainless steel paper guide and the rollerguide.

-   -   8. Feed the paper between the spring loaded Paper Clamp and the        Roller Guide.    -   9. Thread the paper through the Slot below the Roller Guide.

[Close all door guards.]

The manually feed the paper by depressing and holding the Snake Wrap Jogpush button, being sure to feed a sufficient amount of paper to ensurethe Snake Wrap is dispensing properly. The snake wrap paper is cut witha double-edge, carpet knife blade.

The skid storage lift (FIG. 10) can hold up to 10 empty skids. To loadthe skids onto the skid storage lift, open the door guard and place thestack of skids onto the left. Then push the stack against the stops atthe rearmost and right most positions, and close the door guard.

Prior to homing the Palletizer, it is necessary to ensure that the SkidStorage Lift and Pallet Lift are in the lowest position. It is alsonecessary to remove all sticks from the Pick & Place, the temporarystaging area, and the Main Table, and to remove any partial pallets orempty skids from the pallet lift.

Operating Sequence

The pick and place mechanism PP (FIG. 3) removes a stick from the stickdischarge of the Bagger apparatus, and places it on the walking beam WB(FIG. 4). Then the walking beam WB places the first stick against thetemporary hold back HB-1 (FIG. 5). Those steps are repeated until acomplete layer (sixteen sticks) is built. During the building process,the temporary hold back HB-1 and previously placed sticks are pushedprogressively farther from walking beam WB as each of the sticks 1-7 areplaced. After the 7th stick is placed, the temporary hold back HB-1rotates below the level of the sticks, returns to its home position, andthe primary hold back HB-2 begins retaining the layer. The primary holdback HB-1 and previously placed sticks continue to be pushed away fromthe walking beam WB as sticks 8-16 are placed (see FIG. 7).

The row transport RT lowers into position and clamps the completed layeragainst the primary hold back HB-2. The row transport RT and hold backHB-2 transport the completed layer from the layer building area to themain table MT. The offset cylinder OC (FIG. 8) extends and stops the rowtransport RT at the appropriate location for the row offset. The maintable retainers MTR (FIG. 9) clamp the positioned layer. Then, the rowtransport RT and hold back HB-2 return to their home position.

Next, the main table MT extends out over the pallet (FIG. 2) and the rowcut off RCO lowers. The main table MT then retracts while the row cutoff RCO hold the layer of sticks in place. Effectively they are wipedoff the main table onto the top of the load on the pallet. The rowsupports RS (FIG. 14) restrain the layer after it is positioned, and therow tamp RT (FIG. 13) compacts the layers on the pallet as each layer isplaced.

The snake wrap carriage SWC drapes a layer of wrap on top of thecompleted layer, and waits on the opposite side of the pallet for thenext layer to be placed. The row tamp again compacts the layers of thepallet. The foregoing steps are repeated until the pallet is complete,normally when 27 rows are in place.

After completing the last layer of paper wrap, the snake wrap papercutter WPC cuts the wrap from the roll. The full pallet lift FPL thenlowers to its discharge position. The motorized roller table on the fullpallet lift turns on and transports the full pallet to the palletdischarge roller table DRT. It in turn transports the pallet away fromthe pallet building area to allow the operator to remove the completedpallet. The empty pallet shuttle EPS transports an empty pallet from theempty pallet storage lift to the pallet Lift PL to begin building thenext pallet.

While the methods and apparatus for carrying these methods into effect,constitute preferred embodiments of this invention, it is to beunderstood that the invention is not limited to these precise methodsand forms of apparatus, and that changes may be made in either withoutdeparting from the scope of the invention, which is defined in theappended claims.

1. A palletizing apparatus for loading a pallet with successive rows ofcylindrically shaped container end sticks, comprising pick and placemeans for grasping a predetermined quantity of the sticks to form alayer of a pallet, one at a time in succession, and maintaining eachstick in a predetermined orientation, a pallet loading station includinga lift receiving a skid on which a pallet is to be built, said liftincluding a vertically adjustable lift platform for supporting a skid toform the base of a pallet, control means for moving said platform to andfrom a lower skid receiving location and through a range of upperloading locations, said control means including means for adjusting theupper surface location of a pallet being built upon the skid to apredetermined elevation at which assembled rows of sticks are added tothe top of the pallet, a main table and means for moving said main tablebetween a receiving and assembly station and a loading station over thetop of the assembling pallet, said pick and place means having controlmeans for placing the oriented sticks sequentially onto said main tablein a side by side row of the predetermined number of oriented sticks, awrapping supply roll, a moving support for said roll including controlmeans for shifting said roll back and forth to lay the wrapping acrossthe top of each row of sticks added to the assembling pallet, means forattaching a free end of the wrapping supply roll to an empty skid onsaid lift platform, means for transferring each row of sticks placed onsaid main table onto the top of a layer of wrapping, means for passingthe wrapping over the last placed row, and means for dischargingcompleted pallets from said pallet loading station.
 2. palletizingapparatus as defined in claim 1, including a programmable controller forcommanding the sequencing and operation of said pick and place means,said control means for said lift platform and said control means foradjusting the upper surface location of a pallet, said means for movingsaid main table, said control means for shifting said moving rollsupport, and said means for transferring a row of placed sticks fromsaid main table onto the top of a building pallet.
 3. A palletizingapparatus as defined in claim 1, wherein said pick and place meansincludes a traveling gripper which container close about an orientedstick supplied to said apparatus, a staging mechanism including awalking beam member having a moving cradle for receiving a stick fromsaid traveling gripper, and also including a hold back mechanism spacedfrom said cradle to control the positioning of oriented sticks deliveredto said hold back mechanism from said moving cradle, and means fortransferring the an assembly of oriented sticks from said stagingmechanism to said main table.
 4. A palletizing apparatus as defined inclaim 1, further comprising a skid storage station adjacent said palletloading station for storing a quantity of skids, means for aligning andtransferring a skid from said storage station to said lift platform. 5.A palletizing apparatus as defined in claim 4, including meanscontrolled by said programmable controller for sequencing said aligningand transferring means after a completed pallet is discharged from saidpallet loading station.
 6. A palletizing apparatus as defined in claim1, further including tamping means associated with said means fortransferring a row of sticks from said main table and operable to tampthe row of sticks last added to the pallet.
 7. A palletizing apparatusas defined in claim 1, further including pallet discharge meanscomprising a power driven roller tables incorporated in said liftplatform, and means for actuating said power driven roller table todischarge a completed pallet from the palletizer apparatus.
 8. Apalletizing apparatus as defined in claim 7, further including controlmeans operated by said programmable controller to actuate said powerdriven roller table once a pallet has been completed.
 9. A method ofassembling a pallet with successive rows of container end sticks,comprising a) receiving a succession of individual cylindrically shapedsticks each in a predetermined orientation, b) placing the stickssequentially into a rows of each predetermined number of sticks, c)locating a skid at a pallet loading station to form the base of a palletof container end sticks to be built at the loading station, d) attachingthe end of a roll of wrapping material to the skid, e) moving thewrapping material across the skid f) loading successive rows of sticksonto the top of a layer of wrapping, the first row being supported onthe empty pallet, g) passing the wrapping over the last placed rowfollowing a back and forth motion over the successively loaded rows ofsticks until a desired number of rows is automatically built up into acomplete pallet, h) severing the uppermost layer of wrapping from thesupply roll, and I) removing the completed pallet from the loadingstation.
 10. A matter of assembling a pallet as defined in claim 9,including the further steps of a-1) during step (b) initially graspingeach stick with a traveling gripper which can close about an orientedstick supplied to said apparatus to maintain the orientation of thesticks, b-1) depositing each stick onto a walking beam member having amoving cradle for receiving a stick from said traveling gripper, b-2)placing the sticks in succession against a hold back mechanism andalongside each other to control the positioning of oriented sticksdelivered from the moving cradle, and b-3) means for transferring theassembled oriented sticks onto a main table at its receiving position.11. A method of assembling a pallet as defined in claim 10, furthercomprising j-1) storing skids at a storage station adjacent the palletloading, and j-2) aligning and transferring a skid from the storagestation to the pallet loading station.
 12. A method of assembling apallet as defined in claim 11, further including f-1) tamping the row ofsticks last added to the pallet.
 13. A method of assembling a pallet asdefined in claim 12, wherein step (I) includes I-1 actuating a powerdriven roller tables incorporated into the bottom of the loading stationto discharge a completed pallet from the palletizer apparatus.
 14. Amethod of assembling a pallet as defined in claim 13, wherein steps (a)through (I-1) are accomplished automatically by an electronic controllersystem programmed to supply a skid, assemble a predetermined number ofpre-oriented sticks into rows and place such rows on the skid withinterleaved wrapping material, then discharging the resultant loadedpallet.